The bioinformatic and statistical needs of this Program Project are focused and specific. We do not seek to identify large scale interactions among proteins, nor to examine networks of gene expression. Rather, we intend to rely upon conservation of function in evolutionarily distant species to guide us to the identification of essential genes in host defense, and ultimately, to deduce biochemical pathways that protect us against viruses. The unified mission of this Program Project will depend upon the constant access to data deposited by the participants into the Strasbourg, Osaka, and La Jolla Databases, wherein candidate loci will be reported in order that they can be rapidly targeted for deletion, maintained under surveillance in anticipatory resequencing arrays, and annotated within critical regions. In addition, the Program Project aims not only to identify individual genes and pathways that are required for resistance to viruses, but to make a sound estimate of the total number of genes with non-redundant defensive functions. These goals will be met by the Bioinformatics and Statistical Analysis Core Laboratory. It will be responsible for the construction and continual improvement of the three Databases described in Projects 1-3, for the presentation of these Databases in a web-accessible format, for the analysis of microarray data developed at each participating institution, and for the development and implementation of novel statistical methods to calculate the size of the host resistome.